I think he had made in his mind a certain profile of criminals in the neighborhood, saw someone that fit that profile, and was intent on stopping any criminal action from occurring. He was so focused on criminals and crime that it never occurred to him that this could just be some kid walking home from the store. If anything, he had the intent to stop anyone that was going to commit a crime in his neighborhood, even if it meant shooting and killing a criminal. That is the problem I see here. It wasn't Trayvon in particular, it could have been anyone with a hoodie on, walking through that neighborhood late at night.
His biggest problem is that if someone, anyone, fits his idea of a criminal, then he automatically assumes that person is a criminal, and it's okay to use to deadly force if necessary on that person. That, to me, is malicious intent on anyone who happens to fit his profile, and that is very scary to me. It's generous and kind that Trayon's mom thinks it was an accident, but to me, it wasn't. Once he made up his mind that he saw a criminal in his neighbhorhood, it was game on to stop that criminal at any cost. And it's even scarier that he's rationalized what he did so quickly, and has just wanted it to blow over. Being a criminal doesn't mean someone deserves to be shot and killed. And the saddest part is, Trayvon wasn't even a criminal.